If you've worked in the design industry and they've told you these things, and you went ahead and believed it, I feel bad for you.
Glossy isn't designed to "artificially increase contrast", it's meant to give you the full unadultered image. Compared to the matte screens, they have "more contrast" by principle alone.
Ever see a shower door? Compare that to a window. One is anti glare (guess which!), but at the same time, gives an "altered" image of the other side. The other is "glare", but offers an unobstructed view. Which one offers more "accuracy"? I don't know how much dumber I can make it so that you'd understand.
I can cite thousands of credible scientific sources to back me, and all you've got is a subjective bestselling list?
EDIT: I'll try again, and maybe this time you might try and think outside that little box of yours and accept reality. I'm having my doubts about you being in the design industry at all with such amateur responses, since it's a very straight forward matter of fact.
The screen is a barrier. It in itself is nothing but a protective layer between you and the actual light being emitted. The "true" colors are whatever's on the other side, aka the light. That is "TRUE" colors, whether or not it's reflective of whatever it's emulating is another point of debate that's even farther over your head.
Now, are we clear? Light -> screen -> your eyes. That's the path of travel. So, the truest colors you can possibly see is with no cover, just your eyes and the light. Can we agree on that? What's possibly more pure than... nothing? Ok. Good.
Matte screen - what is it? It's a light scattering surface. What the hell does that mean? See picture in my previous post. It diffuses light. What does diffuse mean? Let's not get you too confused. It's a complicated form of the word "change" or "alter". Translation? The "true" light, before it enters your eyes, gets "altered" or "changed" by the matte display because of the roughened surface.
Glossy screen - what is it? A smooth surface. It's basically one giant polarizer (you should be familiar with this, it's YOUR JOB), which basically lets light pass through freely, giving you an unchanged view of the image being presented by the display. Light isn't being diffused.
The smoother a surface is, the less diffusion would occur. The less diffusion would occur, the less an image would be altered. On the other side of the coin, less diffusion = more glare.
Have you ever used a matte mirror? It kinda sucks. It "alters" light quite a bit.
ARE WE CLEAR?
Have fun eating that hat.
EDIT2: As for why pros use matte screens, it's pretty obvious. Never mind the fact that a matte screen can't be used under direct sunlight anyway, so that's null, but there's also the fact that.... there's light IN DOORS. I know right, scary.
You can get glare in doors; in fact, I'm willing to bet more than 80/90/99% of matte users got it for the glare that occurs indoors (a poorly tinted window, any light source in the room tbh). If there's light, there's the chance for glare. Very little buy matte specifically to use the damn thing outside, since it's hard even for matte screens and apple's 300 nits to compete with the SUN. I should know, I've tried.